A considerable number of diseases affecting humans as well as animals are caused by microorganisms, in particular by bacteria. With the discovery of antibiotics, these diseases could be effectively treated, not only curing patients but also reducing the spread of bacterial infections. In certain cases, the use of antibiotics even enabled the extermination of diseases, at least locally. However, since some years an increasing number of bacterial resistances against antibiotics are observed, with some bacteria developing multiple resistances. The occurrence of such pathogens makes it difficult to successfully treat even rather harmless infections, which can nevertheless become life-threatening e.g. to small children or elderly people having weak immune systems. In addition, the resistances lead to the reoccurrence of infections especially in the United States of America and Europe, which had almost disappeared in these regions, as e.g. tuberculosis.
Therefore, there is a need of new compounds having antibiotic effects, i.e. inhibiting bacterial growth and proliferation, and preferably causing bacterial cell death.